Method and apparatus for filling envelopes



Feb. 13, 1945. D 5 GUS-HN -rAL 2,369,563

METHOD 'AND APPARATUS FOR FILLING ENvELoPEs Filed Sept. 10. 1945 'ii i ATTORNEY selected pressure;`

Patented Feb. 13, 1945 Memoir which it is desired man the device;

l 'It' isl Well known' in the art of electric' energy translation devices'to 'll the device with ya 'gasa-'3- ous medium for `Various purposes. Foreitainple;

is `customary to fill the envelope of 'an incandescent lamp witlr an inert' 'gas to-r'educe vapori-` zationof'tlreriilarnent. Although such afm'ed'urn is'sonretiines :used in vother 'devices as'radi'oftubes" anddischarge'lamps for'the' saine purpose; a gase'olu's medi'urnfi's 'morel generally" employed in these latter devices for imparting"l thereto desired'V oper-4- will uec'omeobveus-tethose 'skilled' the art fbyf retereneeto the accompanying drawing vvlfrereintf` Figure'- 1 is' more or `ess'of fa* schematic' illustraf tionof the apparatus ofthe presentirivexitiorr and' showing the' most' essential partslin crossesection..

, exhausted and 4iilled-r with: a gaseous mediumras ating characteristics; I 'n ymany discharge tube's and t lamps their operation isI dependent notV only the gaseous' lmedium* withv which they jare" filled but more signifcan'tl'y the'pressure of the ineliiuniv since thev latter often' determines 'the'v voltage -at which: they'operate and the currentv ilo'w therethrough; l f

' Forthis reasonit ism'pe'rative that' 4the pressure` of the gaseous mediunr bei' 's'ubstalritfall'l??A exact. However, inthe prior' art,` this has beena troublesome problem resulting in' many devices' being rejected inthe process of manufacture becausexoffftlreir failure to meet fixed' standards ovoltage` and current fdue to variation in' .the'gas freesurfe: To' obviate this; rather elaborateand: eimensiv'e''eqiiipriier'it'v4 has heretofore" been r'e-,-

aeeuratepressure. f y `Et-isaccordingly'arr object' of 'thev taine "with a: gaseous 'medii'miLIV at aprecise-fprie-L; Anetherobjeetj er uieereseht'invenuon ijs "the provi's'ion'j of anl 'apparatus for 'n1-ling" a sea-leuy com tainer with a gaseous-medium a`t a precise preselectedpressure. y Y y .n *I l i `AAnother object 'ofthe prese 't invention is the' provision of an apparatus lof relatively'sinipieand tionto provide a method of filling ay sealedcona' economical construction 'for filling a vrsealed con#A v selected pressure:

tilt-further objecto'fthe present invention 'isthe" provision ofapump vfor controlling the precise y pressure o'fl thegfaseous medium with which' the' electric energy transletibnfeviee is enea.,

argon, neon, or the like, to facilitate starting'offa discharge therein, and. since the starting voltage is dependent' on kthe" pressure o'f'th'e gas, the 'latter must be substantially-exact. v f [The: yexhaust stem :Bf of thev lamp y5 is connected by atub'e 1 itozas-three-Way vali/alshown` generally atl 8. In wl'iat-iis" indicated as 'the first positionofi theivalv'ed asubstantially U-'shaped port, 9 estab lishes communication between the tube 'f and a tube l0*- .le'ading to av vacuum Vpu'rrip I2 for the purpose of evacuatin'gthe lamp 5. After jcome plete exhaust ofthe latter `the valve \8 is tix-medito position 2? which. thusy shifts the port'v 9 so that'- c'mmunicationl is establishedbetween at tube-13,. constituting 'a braucht ofV the. tube 1f leadingf'tol the lampi, an'dl a: tubet4 extendingA through'a fga's pressureregulatorv ISto afsourceiofsupply sueltasa tank or cylinder I6. The values' H 'arewregua lated so that Athe lamp Eris filled with gasffrom the cylinder l`6' to a pressure slightly in excess of that finally desired for the lamp which pressure will be indicated by' theg'auge I8 y .Next the Valve 8 isiv rotated toits third position so that `the port 9 will establish communication. between another/ tube |9 also' constituting ya', branch of tube 1 leading to the lamp 5, and a further tube 2U leading t0 a pump 2'2,` Although this pump'ma'y be eff `the-l-ro'tary o'r piston ty'p'e it is-slown as comprising' aeylinder v231V pioyi'cltlfy with(V detachable headwthrdugh Wh'cli'a pistoni rod 25 extendstoapiston 26- within-'the cylinder' 2"-3'; the piston rou being lreciproc'ated' tyran leleetrie: motor (fno't s ho'vvn) The opposite cl'o'sed end-"fdr" the cylinder 2 3isprovided vvitha spring pressed iil'e't' valve 2,1" aligning with the tube -201andfa similar type outlet' 'valve -28"W1ii`ch exhausts toltne atmosphere. u

The closed end of the-cylinder 23 "is provided' with an extension forming a compression chaineI ber'2'9' 'containing afpiston 30 which is adjustable within the chambervzsey means-efe conteniendo szaridftlireaded shaftl as'fortue purpose offener-1- ing at will the capacity of the compression chamber 29 and hence the volume of the gas therein. Although the compression chamber 29 is shown as an integral part of the pump 22 it may be separate therefrom but connected with the pump by a conduit when desired so that a standard pump may be utilized. On the other hand the capacity of the cylinder 23 is fixed at some definite figure of say 1000 c. c.

Whenever it is desired to fill a lamp at a giveni pressure the lamp, as above mentioned, is filled at a pressure in excess of that required. The I pump 22 is then operated to pump the gas into the cylinder 23 after which the .volume is decreased by compression with some of the gas being exhausted to the atmosphere through the outlet valve 28, while the remainder is trapped I When equilibrium is established for a given condition then:

1,1760 mm.) (1 c. c. .76 mm.) 1000 c. c.)

due to the fact that the capacity of cylinder 23 is fixed and hence the volume of the expanded gas is about 1000 c. c., while the pressure in the compression chamber 29 is fixed at atmospheric pressure of 760 mm. thus establishing a definite ratio between the pressure and volume of the gas in the cylinder 23 and the pressure and volume of the gas in the compression chamber 29.

Assuming it is desired to fill the lamp 5 at. pressure of 4 mm. the lamp is rst lled from the tank I6 at a pressure of say 6 mm.v In order to ascertain the required volume for the compression chamber 29 when a pressure of 4 mm. is desired in the lamp 5 the above formula is the applied as follows: i

VA 760 mm.=4 mm. 1000 c. c. z

which gives v V (4)(l000\c. c.)

" VA=5.26 c. c. l

Having thus determined the Irequired capacity or volume for the compression chamber 29, the control knob 32H is then rotated so as to move the piston within the chamber 2 9 until this desired capacity or volume of 5.26 c. c. is obtained. To facilitate such adjustment the threads on the shaft 33 may have a definite pitch and number per inch corresponding to a desired .capacity or volume in cubic centimeters within the chamber 29 anda suitable gauge or other indicia provided on the shaft 33 will reveal at a glance thevolume withinthe chamber at any positionof the shaft 33. y .i During the suction or intake stroke of the pis' ton 25 gas from the lamp -5 (at 6 mm. pressure) is drawn into thefcylinder 23 and upon the compression stroke inlet valve 21 closes and outlet valve 28 opens exhausting the gas from the cyl inder 23 to the atmosphere except for the volume compressed in the chamber 29. Continued reciprocation of the pisto-n thus withdraws gas from the lamp -5 and exhausts it to the atmosphere until the volume of gas (approximately 5.26 c. c.) compressed within the chamber 29, when expanded to Whole volume of the cylinder 23, equals the pressure desired in the lamp or 4 mm. pressure,

at which time equilibrium is established since the pressure in the lamp 5 is equal to the pressure of the' expanded gas within the cylinder 23 and continued operation of the pump 22 will have no f effect on further reduction of gas pressure. The

lamp 5 is then-sealed-of in the customary man- -ner such as by applying fires 34 to the exhaust stem 6 after ,which the lamp is ready for basing and complete fabrication.

. vThis may be appreciated by reference to the graph of Fig. 2 wherein the ordinate represents gas pressure and the abscissa time of pumping. The curve A indicates the pressure of the gas in the tank, i. e., initial filling of the lamp at a pressure in excess of that desired, and the line B indicates the preselected desired pressure in the lamp. After a few minutes of pumping the pressure is decreased from that of the initial filling to that desired and, as shown, continued pumping has no further effect on the final lamp pressure, as previously mentioned.

` `It. thus becomes obvious to those skilled in the art that a method of and apparatus for exhausting and filling the envelope o-f an electric energy translation device with a gas at a precise preselected pressure is herein provided. Moreover, this is accomplished primarily by utilizing a pump provided with an adjustable compression chamber so that the area of the chamber can be regulated to preselect the volume of the gas trapped therein. When such gas is expanded to the whole volume of the adjacent connecting cylinder it will finally be pumped to a pressure equal to that preselectedfor the envelope of the device.

Although one specific embodiment of the present invention has been shown and described it ls to be understood that still further modifications .thereof may .be made without departing from the spirit and scope of the appended claims.

We claim:

l. The method of filling the envelope of an electric energy translation device with a gas at a preselected definite pressure comprising filling the envelope with gas from a source of supply and at a pressure in excess of the desired preselected pressure, pumping the gas from the envelope into a normally closed chamber of definite capacity, compressing a preselectedvolume of the pumped gaswithin the chamber while exhausting the remainder until the pressurev of such preselected volume when expanded to the definite xed volurne of the chamber equals the pressure desired inthe envelope, and sealing-off the envelope.

2. I'he method of filling the envelope of an electric energy translation device withk gas at a preselected definite pressure comprising filling the envelope with gas vfrom a source of supply and at a pressure inv excess of the desired preselected pressure, pumping the gas from the envelope into a normally closed chamber of dente volumetric fcapacity, cyclically compressing a preselected vglume of the pumped gas within the cham-ber whileexhausting the remainder and expanding such volume to the denite iixed volume of the y chamber until equilibrium .is established between the pressure of the expanded fixed volume and the pressure in the envelope, and sealing-off the envelope. g

3. An apparatus for filling the envelope of an electric energy translation device with a gas at a definite` preselected pressure comprising a source of gas supply connected to said envelope for lling the latter with gas at a pressure in excess of that desired, means for pumping gas from said envelope into a normally closed chamber of denite volumetric capacity to decrease the pressure in said envelope, and means for compressing a preselected volume of said gas Within said chamber while exhausting the remainder during pumping of said envelope which compressed volume when expanded to the denite xed volumel of said chamber finally establishes af pressure equilibrium with the preselected pressure ldesired in said envelope after which said rst mentioned means becomes automatically inefectivegto further decrease the gas pressure in said envelope.

`4. An apparatus-for filling the envelope of an electric energy translation device with a-gas at a definite preselected pressure comprising a gas supply connected to said envelope lforlling the latter with gas at a pressure in excess of that desired, and means connected to said envelope for reducing the initial filling pressure within said envelope to that preselected including. a pump provided with acylinder havinga predetermined fixed volume and operable to decreasethe pressure in said envelope, a compression chamber `communicating withthe lcylinder of said pump for compressing a preselected volume of said gas while exhausting the remainder during pumping' desired, and means connected to said envelope for decreasingthe initial illing pressure Within' said envelope to r that preselected including a pump provided with a cylinder having a predeterminedflxed volume and an intake valve for decreasing the pressure in said envelope, an outlet Valve for said pump to exhaust said gas to the atmosphere, a compression chamber communicating with the cylinder of said pump ifor compressing a preselected volume of gas during exhaustion thereof tothe atmosphere, and said pump being operable to expand the preselected volume of gas to the whole volume of its cylinder vuntil the pressure of the expanded volume establishes equilibrium with the pressure in said en velope rendering said pump thereafter ineiective to further reduce the pressure in said envelope and thus xing the pressure in said envelope at that desired. l DANIEL S. GUSTIN. DANIEL MULLAN. 

